nim-libp2p/libp2p/muxers/mplex/coder.nim

79 lines
2.3 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2018 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import chronos, options, sequtils, strformat
import nimcrypto/utils, chronicles
import types,
../../connection,
../../varint,
../../vbuffer,
../../stream/lpstream
logScope:
topic = "mplex-coder"
type
Msg* = tuple
id: uint
msgType: MessageType
data: seq[byte]
proc readMplexVarint(conn: Connection): Future[Option[uint]] {.async, gcsafe.} =
var
varint: uint
length: int
res: VarintStatus
var buffer = newSeq[byte](10)
result = none(uint)
try:
for i in 0..<len(buffer):
await conn.readExactly(addr buffer[i], 1)
res = LP.getUVarint(buffer.toOpenArray(0, i), length, varint)
if res == VarintStatus.Success:
return some(varint)
if res != VarintStatus.Success:
buffer.setLen(0)
return
except LPStreamIncompleteError:
buffer.setLen(0)
proc readMsg*(conn: Connection): Future[Option[Msg]] {.async, gcsafe.} =
let headerVarint = await conn.readMplexVarint()
if headerVarint.isNone:
return
debug "readMsg: read header varint ", varint = headerVarint
let dataLenVarint = await conn.readMplexVarint()
var data: seq[byte]
if dataLenVarint.isSome and dataLenVarint.get() > 0.uint:
debug "readMsg: read size varint ", varint = dataLenVarint
data = await conn.read(dataLenVarint.get().int)
let header = headerVarint.get()
result = some((header shr 3, MessageType(header and 0x7), data))
proc writeMsg*(conn: Connection,
id: uint,
msgType: MessageType,
data: seq[byte] = @[]) {.async, gcsafe.} =
## write lenght prefixed
var buf = initVBuffer()
let header = (id shl 3 or ord(msgType).uint)
buf.writeVarint(id shl 3 or ord(msgType).uint)
buf.writeVarint(data.len().uint) # size should be always sent
buf.finish()
await conn.write(buf.buffer & data)
proc writeMsg*(conn: Connection,
id: uint,
msgType: MessageType,
data: string) {.async, gcsafe.} =
result = conn.writeMsg(id, msgType, cast[seq[byte]](data))